Contact Information

Tab navigation

Overview

I work on cognitive algorithms to provide decision support for hard combinatorial feasibility and optimization problems as they arise in the context of real-world applications. Methodologically, I am especially interested in the integration of methods from mathematical programming, approximation theory, and artificial intelligence, which has proven very successful in boosting the solution efficiency for discrete feasibility and optimization problems. While an important aim for me is to provide actual software systems that can tackle real-world applications efficiently, the abstraction and generalization of originally problem-tailored approaches to standard solution methods that facilitate algorithm design and algorithm engineering for constraint satisfaction and constrained optimization is a key part of my work. Main contributions to this line of research were:

Symmetry Breaking

Invented Symmetry Breaking by Dominance Detection (SBDD) and Structural Symmetry Breaking (SSB). SBDD is one of the most cited papers in CP in the first decade of the new millennium.

Presented the first polynomial method for breaking piecewise variable and value symmetry simultaneously at IJCAI'05.

Proposed an integration of static symmetry breaking with restarts at the model level. This method defines the state-of-the-art for breaking piecewise symmetry, outperforming competing approaches by one order of magnitude. (Best paper nomination CP'08)

Introduced low-bias algorithm portfolios 3S and CSHC which were used to devise portfolios for SAT (winning solvers in International SAT Competitions 2011-2013)

Developed Instance-Specific Algorithm Configurator (ISAC) which generalizes both algorithm portfolios and algorithm configuration by choosing an algorithm/parametrization with respect to the given input. ISAC was used to devise a MaxSAT portfolio which won 6 out of 11 categories in the 2013 and 3 best solvers in the 2014 MaxSAT Evaluation.

Applications

Set Covering

Airline Crew Scheduling

Capacitated Network Design

Resource Constrained Shortest Paths

Experiment Design

Combinatorial Designs

Automatic Recording

Graph Partitioning

Sensor Placement

Pipeline Terminal Scheduling

Trade Settlement

Footer links

IBM is not responsible for, and does not validate or confirm, the correctness or accuracy of any user content posted. IBM does not endorse any user content. User content does not represent the views or opinions of IBM. IBM, in its sole discretion, reserves the right to remove any content.